1. Field of the Invention
The present invention relates generally to transaction processing terminals, and more particularly, to a transaction processing terminal which can be connected to a telecommunication line connected to a communication terminal and a transaction processing system including a transaction processing terminal.
2. Description of the Prior Art
Recently, stores have begun using credit authorization terminals (referred to as CAT's hereinafter) for performing credit card authorization processing, that is, making an inquiry to a host as to whether or not payment can be made using the credit card and displaying the result of the inquiry.
In conventional CATS, both a program for performing the above-described card authorization processing and data are necessary for such a program for performing card authorization processing are stored in a memory. Known methods for storing the program and the data in this memory are as follows:
(1) The entire program is stored in a ROM (read-only memory) in the CAT. A table is constructed by a key operation or by transmitting data to be stored from a host through a telecommunication line.
(2) Only a basic portion of the program is stored in the ROM, and an application program which may be changed for each customer is stored in a RAM (random access memory). The application program is transmitted through the telecommunication line, and the table is set in the same manner as for case (1).
In above case (2), it is not important to transmit the application program by key operation because to do so is almost impossible. However, it is important to transmit the application program through the telecommunication line. In addition, techniques for doing so comprise a method for dialing from the CAT to the host and a method for dialing from the host to the CAT. Recently, the latter is preferable in that an extra burden is not imposed on an operator on the side of the CAT and in that the load of the host can be averaged.
The conventional CAT and a telephone may be connected to a single telecommunication line. In such case, when a calling signal externally applied is received, it cannot be determined whether the calling signal is a call for constructing the above-described program or the like or a call for general telephone conversations. Therefore, in order to construct the program or the like by transmission from the host, the line must be preconnected only to the CAT before the incoming call from the host is received. However, in the case of such connection, when transmission is not made from the host, the above-described telephone cannot respond to an outside call for general conversation because it is not connected to the line, so that utilization of the line is limited.